Violet-color lake and process of making same.



UNITED STATES PATENT OFFICE,

RICHARD KIROHHOFF, or ssoss-mcn rnsranns, AND LEO KERKOVIUS, OF FRIEDENAU, GERMANY, ASSIGNORS To ACTIEN GESELLSCHAFT FUR ANILIN FABRIKATION, or BERLIN, GERMANY.

I No. 820,052.

Specification of Letters Patent.

Patented May 8, 19cc.

Application flied October 17, 1906. Serial No. 283,193-

To all whom it may concern:

Be it known that we, RICHARD KIRCHHOFF, of Gross-Lichterfelde, near Berlin, and Lao Knnxovws, of Friedenau, near Berlin, in the Kingdom of Prussia, German Empire, have invented new and useful 1m rovements in the Manufacture of VioletPCo or Lakes and Processes of Makin Same and we do hereby declare that the fol owing is a foil, clear, and exact description of the invention, which will enableothers skilled in the art to which it appertains to make and use the same.

We have found that one can obtain valuable violet-color lakes from the monoazo dyestufi which is reduced by combining the diazo compoun of the para-amidophenyl- 1.2-naphthyl-triazol-3.8-d1su lfonic acid.-

into the salts of an alkalineearth metal, of

. an earth metal, or of another suitable metal.

, triazol-3.8-disulfonic acid which is to Azo colors of a constitution like the above have heretofore notbeen used in the art of lake-making. Hence one could not foresee whether such an azo coloring-matter would be a suitable startin product for the manufacture of valuable is e pigments or not.

As to the manufacture of the above dyestufi", the para-amid ohenyl-I .Zmaghthyle diazotized and lthen combined with the betanaphthol-3.6-disulfonic acid is obtained in the following manner: The l-naphthylemin 3.8-disulfonic acid so,n NH,

is acted on in the usual manner with the diazo compound of para-nitranilin and th resulting monoazo dyestufi' S0 11 NH,

treated with a suitable oxidizing agent such asperoxid of lead, obtainin thus the aranitrophenyl -1 .2-na'phthyl trlazol- 3.8 isulfoniej acid which on reduction yields the above-named corresponding amide compound serving as j starting product for the diazetiaing and comblmng process.

In order to manufacture such violet lakes,

the alkaii salts of the said dyestufi are dissolved or sus end ed in water and a solution of a metallic sa t of the above-named classesas for instance, a salt of barium, calcium, strontium, ma esium, or the oxid or hydroxid of one 0 these metals or a mixture of such compounds-is added in the cold or whileheatm Itispreferable to add'before or after precip tation a suitable substratuin such as sulfate of calcium, h droxid of aluminium, or the like. The la es are then filtered and dried. They ossess a clear violet color and are most diflicu tly soluble or nearly insolublein water. When applied to a surface, they yield clear violet coatings of a good fastness a ainst the action of light.

The foil owing example may serve to illustrate our invention, the parts being by weight: One hundred parts of a aste contaimng about twenty or cent. of t e sodium salt of the azo d est which is obtained by combining the diazo compound of the garaamido-phenyl-L2-naphth l-triazol-3.8- isulfonic acid with beta-nap thol-3.6-disulfonic I00 acid, are well mixed with about one thousand partsof water and thenthe mass heated to 80 to 90 centigrade. Thenzis added thereto, while stirring well, an a ueous solution of sevent to eighty parts 0 crystallized barium c lorid and for some further time agitated, the tem erature of 80 to 90 being maintained. 0w one thousand parts of a freshly-prep ared paste of aluminium hydroxid containln about three per cent. thereof are introduce the mass being well stirred. Agitation havin been continued for some time, one heats t e whole to the boil and filters under ressure, whereafter the residue is dried an very finely ground. The clear violet powder thus obtained when applied to a surface yields clear violet coatings o a good fastness to light.

It is obvious to those skilled in the art that there may be made many variations of the foregoing example, relating to the proportions of the ingredients as well as to the special kind of the alkaline earth metal used or the substratum used, without departing from the scope of our invention.

Having now described our invention and in what manner the same can be carried out, what we claim is- 1. The process for the manufacture of new violet-color lakes prepared by converting an alkalisalt of the azo color as defined in the foregoing specification, into an insoluble salt, said lakes being distinguished by a clear violet color, a great insolubility in water and a good fastness to light, these lakes being split up by the action of a strong reducing agent yielding thereby para-amido-phenyl-l. 2-naphthyl-tr1azol-3.S-disulfonic 8.0M] besides an amido naphthol-disulfonic acid.

3. As a new article of manufacture the new violetcolor lake prepared by converting the azo dyestufl paraamido-phenyl-L2-naphthyl-triazol-S.8-disulfonic acid-azo-2-naphthol-3.8-disulfonic acid into an insoluble salt by means of barium chlorid in the presence 0 aluminium hydroxid, said lake being a violet powder practically insoluble in water and insoluble in alcohol, which powder when applied to a surface yields clear violet coatings and which powder when treated with the solution of an alkali in the heat is decomposed and converted into the corresponding alkali salt of the said d estuff and from which solution of the alkafi salt, by a treatment with strong reducing agents, para-amidoephenyl- 1.2 naphthyl triazol 3.8 disulfonic acid is obtdained besides amido-naphthol-disulfonic acl In witness whereof we have hereunto signed our names, this 1st day of October, 1905, in the presence of two subscribing witnesses.

RICHARD KIRCHHOFF. LEO KERKOVIUS.

Witnesses HENRY HASPER, WOLDEMAR HAUPT. 

